Inflatable test plug



May-V28, 1940 E. F. scHULDT INFLATABLE TEST PLUG original Filed April 2. 1957 2 Sheets-Sheet 1 QNR i 4r r/ r/ May 28, 1940- E. F. scHULDT' INFLATABLE TEST PLUG original Filed April 2,y 1957 2 Sheets-Sheet 2 Patented May ze, 1940 Y UNITED STATES ml-'rislv'l"v oFFics A ary 27, 1940. Divided and this applicaticmA y December 20, 1937, Serial No. 180,698

3 Claims. v (Cl. 13S-93) This application is a division of my copending application, Serial No'. 134,563, filed April 2, 1937, now Patent No. 2,192,155 of February 27, 1940, for Method of and means for locating leaks in a gas main or the like. Y

This invention relates to a method and means for locating leaks in gas mains, underground iiuid transmission conduits and the like, and more particularly is concerned with the location oi' fluid leaks in low pressure distribution mains. In the parent application, identiiied above, the means and apparatus disclosed and claimed make possible ka material reduction of time and labor necessary for locating and repairing leaks inlow pressure gas mains and the like, land the principal object of the present invention is the pro- .vision of a new and improved form of stopper or Vtest plug which, While especially useful in connection with thek above A.mentioned method and apparatus, is capable of 'other uses in connection with the stoppage of fluid flow through a conduit.

More specifically, it is an object oi this invention to provide an iniiatable test plug of simple and sturdy construction and which can be readily inserted through a relatively small opening in the main to be tested orvplugged, and it is a furf ther objectl of the present invention to provide f a construction of this character which can be inserted through relatively long `distances in the pipe.

Particularly, itis an object of this invention to provide an inatable test plug which includes an interior spring `member connecting theV ends of the inflatable Vbag so as to facilitate the `proiection of the bag to the point desired. Another 4object of the present invention in this connection is the provision of pipe engaging means for the bag. An inflatable test bag of this construction is especially useful where it is the iirst of a series of bags connected together. It is also an object Y of the present invention to provide such an .inflatable test bag with new and improvedmeans for transmitting iluid under pressure through the bag but entirely out of communication with the Vinterior of the bag. kA bag of this character is especially adapted for use with other bags where it may be desired to determine the pressure conditions between two or more of such bags, asin the use of my method of locating leaks disclosed in the above identied parent application. A bag cf this character, however, is not necessarily limited to such use.

The above and other advantages of this invention will be apparent Ato those skilled in the 4-art cation;

after a consideration of the following detailed description of the preferred means iii-which the principles of my invention have been embodied.

In theaccompanying drawings:

Figure l is a longitudinal sectional View ofv one form of inflatable bag, which can be used for the rear bag in the apparatus disclosed in my parent application; y

Figures 2 and 3 are enlarged sections taken along the lines 2-2 and 33, respectively, of lFigure l;

' Figure 4 is a longitudinal sectional view o1" another form o-f bag, which can be used for the leading .bag in the apparatus of my parent appli- Figure 57and -6 are enlarged sections taken along the lines 5--5 and 6-6 of Figure 4.

Referring now more particularly to Figurel, in testing pipes, such as gas mains and the like, for leakage it` is usually desirable to stop oi the pipe or main at one or more points in order to perform the desired tests,"and in the accompanying drawings the reference'numeral 3l) indicates, byway lof illustration, a gas mainin which a test opening is made, as at 32, through which an inflatable test unit may be inserted, consisting either of a single bag in case the main 3l! is merelyto be plugged or consisting of two or more bags in case certain `tests are to be made on sections of the main 30. Preferably, the Vmain 1s closed by any sealing compound 33, such as soap or the like. l

ACine type of inflatable test 'plug' incorporating the principles of the present invention is indicated in Figure l by the reference numeral 34. The test plug 34 includes an expansible bag or Abulb 35 having nipple-like ends 36 and 3i, the

nipple end 31 enclosing a tubular metallic bushing or sleeve member t0 to the' outer end of which a tting il is secured, as by Welding or the like. The iitting is threaded and receives a coup-ling nut 42 to which is secured a coupling member 4,5 having two conduit sections i6 and ill incorporated therein. Each ol' these-conduit sections comprises a tube which extends into the ,tting `4l, the latter having two bores 48 and'ii to snugly receive the inner ends of the tubes-46 and 4l, and the inner end of the coupling member l5 has a flange 5l which the outer end of the coupling member 42'engages. Preferably, a gasket 53 provides a leak-tight connection at this point.

The coupling member i5 forms one end of a dual-ported conduit, indicated in its entirety by lthe reference numeral 56'. The 4conduit 56 is` provided 'with two generally parallel bores or tubes 51 and 58 which communicate, respectively, with the tube sections 48 and 41. Preferably the conduit member 56 is formed of molded rubber or the like and the tubes 51 and 58 are preferably in the form of copper or similar flexible tubes which are embedded in the rubber of the conduit member 56, In order to provide forv propelling the inflatable test plug 34 for considerable distances Within a main, the flexible conduit member is provided with a steel tape 60 extending along the member 56 and fastened by screws 6| or the like to the coupling member 45. 'I'he conduit member 56, either with or without the steel tape 80, is sufficiently iieXible to permit inserting the unit 34 through the opening 32 in the main 30 and pushing it along on the inside, and if it is desired to know the distance that the unit 34 has been moved, the steel tape 80 may be provided with graduations 82.

A bushing or sleeve member 18 is disposed within the other nipple-like end 36 of the bag 35, and if desired suitable clamps 1| and 12 may be used for securing the bushings or sleeve members 40 and 10 to the bag 35. A spring member 13 is rigidly and permanently secured in any desired manner, as by welding or the like, to the bushings or sleeve members 40 and 10 and serves thereby to determine the actual length of the inatable bulb or bag 35. Since one end of the spring member 13 is permanently and rigidly fastened to the sleeve 40, and since the latter is, in turn, rigidly fastened to the coupling member 45 to which the pushing tape 60 is connected, it will be seen that the members 60, 45, 40, 13 and 10 form one continuous spring member by which thrusts may be applied to shift the inflatable unit 34 from place to place within the main 30 and that the resiliency ofthe spring parts 60 and 13 permit the unit to accommodate bends, curves, elbows and the like in the main 30.

One of the conduit tubes, such as the tube 41, communicates through the sleeve or bushing member 40 with the interior of the inflatable bag 35, and the other tube 46 communicates with a tube 15 to which a flexible section 16, preferably formed of rubber or the like, is secured. The end of the section 16 opposite the tube 15 is connected to another tube 11 which leads into the sleeve member 10 and out of the latter at 18 so as to be in communication with the space in the gas main 30 beyond the unit 34.

In operation, the unit 34 as shown in Figure 1 may be inflated by compressed air or other source directed thereinto through the tubular sections 58 and 41, and if desired, access to the space in the gas main beyond the unit 34 may be had through the tubular sections 46 and 51, and the traversing tubes 15, 16 and 11. It will be noted that the latter extend from one end of the inflatable bag 35 to the other but are entirely out of communication with the interior thereof.

Where an inflatable test plug of this kind is to be used in association with another unit, as in the apparatus disclosed in my copending parent application, another conduit section, v'indicated in its entirety by the reference numeral 80 may be connected to the bushing or sleeve member 10. To this end, the conduit 80 may be cemented or otherwise secured or fastened to a coupling member 8| which is threaded, as at 82, to the outer end of the bushing 10. The coupling member 8| also receives one end of a resilient spring member 83 which extends along the conduit 80 on the inside thereof and, in effect, forms a continuation of the resilient spring member 13 and the tape 80. Either or all of the spring members 60, 13, and 83 may be flat, or they may take the form of a helically coiled resilient member. In all cases, however, the spring members should be so formed as to be capable of transmitting thrusts and to permit pushing the unit 34, together with any other unit or units connected therewith, to be moved from place to place in the main 30 as desired.

'I'he principles of the present invention can also be incorporated in the form of inflatable test plug shown in Figure 4, which is constructed so as to operate with the unit 34 described above. However, so far as the present invention is concerned, neither inflatable unit is limited in its application to an association` with the other, inasmuch as either may be used separately if desired and as conditions warrant.

Referring now to Figure 4, for convenience of illustration I have shown my second form of iniiatable test plug as attached to the conduit member 80 referred to above. The inatable test plug of Figure 4 is indicated in its entirety by the reference numeral and includes an expansible bag or bulb |0| having nipple-like ends |02 and |03. Within the end |02 is a bushing or sleeve member |05, the outer end of which is threaded, as at |06, and receives a coupling member |01 to which the ends of the conduit member 80 and the spring member 83 are attached. As will be clear from Figures 1 and 4, opposite ends of the member 80 are substantially identical in construction. 'I'he other end |03 of the expansible bulb |0| is provided with a bushing or sleeve member ||0, and a flat spring member is connected at opposite ends to the bushing or sleeve members and ||0 in any suitable manner, such as welding, brazing, or the like. Clamp members ||3 and ||4 may be provided for securing the nipple-like ends |02 and |03 to the associated bushings |05 and H0. As will be clear, the spring member serves as an extension of the spring member 83, and likewise is not necessarily a flat member but may be a helically wound spring member if desired. Where the two inflatable test units 34 and |00 are used together, the inflating pressure .for both of the bulbs 35 and |0| may be transmitted from the tube 58 to the first bulb 35 and from the latter through the conduit section 80 to the bulb |0|. If used separately, the bulb |0| may be inflated in any suitable manner by fluid transmitted through the conduit section 80 from any convenient source, and if used with the unit 34, that source may be the same source from which the unit 34 is inflated, namely, the tube 58.

In order to facilitate the use of the unit |00 as a first of a series and to guide the same through bends, curves, elbows and the like in the main 30, the bushing or sleeve member l0 is provided with suitable pipe engaging guiding means. At its outer end, the member ||0 is recessed, as indi cated at |20, the receive the reduced end |2| of a guide supporting member |22. The member |22 has a groove |23 formed in its reduced end, and a transverse pin |25 is disposed in the outer end of the bushing 0 and is received in the groove |23 so as to hold the member |22 in position axially but to permit the same to rotate with respect to the member ||0. Secured to the forward end of the member |22 is an elongated resilient arm member |28 which enters into a slotted portion in the. end of the member |22 and is secured therein `by means of a pair of rivets |30.

The outer or forward end of the elongated resilient arm member |28 is provided with a suitable pivot pin |32 upon which two oppositely'disposed semi-spherical roller .members |33 aremounted I for free rotation.

By the provision of the guiding member |28, as a push is exerted upon the spring member 83 and.

transmitted to the spring member H, rollers |33 will guide the unit |00 around bends. or the like This construction is especially advantageous where oisets to clear a vault4 in th'e gas main 30.

or underground manhole are encountered, in

which case vthe unit or units must be guided through 45 and by the provisionof the rollers |33, this can be accomplished without any substantial buckling or distortion of the parts.

. The gas bags or bulbs 35 and |0| are preferably made of a material, such' as rubber or the like, which may .be treated' to provea wear-resisting surface, and al1 joints and connections may be cemented, if desired, in order to insure against loss of pressure.

While I have described above the preferred` means in whichL the principles of the present invention have been embodied, it is to be understood that my invention is not tov be limited to the particulardetails shown and described but that, in fact, widely different means may be em- -Y ployed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. .A test plug for gas mains and the like comprising an iniiatable bulb, a bushing secured withsaid spring ymember to propel the bulb along the interior of avpipe, and pipe-engaging supporting means connected withthe other bushing.

2.v A test plug for gas mains andthe like, comgprising an inflatable body member having'oppositely extending smalldiameter nipple portions at opposite ends thereof, a small diameter-bushing 'disposed Withineachof'saidnipple portions,

cylindrical clamps 'of small diameter for securing saidnipple portions to saidl bushings in leaktight relation, and a flexible spring rod of i'lxed length joining the bushings whereby said test plug may be inserted through an-opening in said main of a diameter not substantially larger than 1 the ydiameter' of said cylindrical ing said spring rod.

3. A test plug for gas mains and the like, comprising an inflatable body member having .op-

clamps by bend-V posite'ly'extendingsmall diameter nipple portions at opposite ends thereof, asmalldiameter -bush, f

ing disposed within each of said nipple portions, a fiat resilient longitudinally extending spring member disposed within said inflatable body pori tion and secured at its oppositeends within each of said bushings, and cylindrical clamps of small .diameter for securing said nipple portions to said bushings in leak-tight relation, whereby said test plug may be inserted through an 'opening in said mainof a diameter not substantially larger than `the diameter of said cylindrical clamps;

ELMERv F. SCHULDT; 

